In a capsulated drug in which a hard capsule consisting of a cap and a body is filled with a drug, generally, the drug filling the capsule is powdery, granular or liquid. In some practical cases, however, a capsule consisting of a cap and a body is filled with a predetermined number of tablets, to produce a tablet-filled capsulated drug.
Specifically, in some cases of drugs, the dose for one-time medication has normally to be changed according to the patient's symptom, age or other conditions. In such a case, when the drug is supplied in the form of tablets having a predetermined unit quantity, it is easy to change the number of tablets for dosage according to the patient. However, there may arise an inconvenience. Where the dose is controlled in terms of the number of tablets for dosage, the patient must count the tablets at the time of dosage for the purpose of taking the tablets in the number according to the patient's symptom and/or age, which is troublesome. In addition, it may be necessary for some patients to take a very large number of tablets at a time. In view of this problem, a capsulated drug may be produced preliminarily by filling a capsule with tablets, each containing a predetermined unit quantity of an active ingredient or ingredients, in the number according to the patient's age and/or symptom, and put to medication, whereby the burden on the patient at the time of medication can be alleviated. In the case of a combined dosage of a plurality of kinds of drugs, a single capsule may be filled with the plurality of kinds of drugs according to the disease and/or symptom, etc., whereby multi-component drugs according to a plurality of kinds of diseases and/or symptoms, etc. can be prepared as capsulated drugs.
Here, while a capsulated drug filled with a powdery or granular drug is produced by automatically filling each of capsules with the powdery or granular drug by a capsule filling machine, an automatic tablet filling machine for filling each of capsules with tablets in a similar manner has also been proposed. In this case, in order to make the capsulated drug as small as possible in size for the purpose of alleviating the burden on the patient at the time of medication, filling a capsule with ordinary flat tablets is carried out by a method in which the capsule is filled with the plurality of flat tablets under a flat state.
Herein, the expression “the flat tablet under a flat state” means the state of the flat tablet having its radial direction set horizontal (in the transverse direction) and its thickness direction set in the vertical direction (the longitudinal direction). On the other hand, the expression “the flat tablet under a standing state” appearing later means the state of the flat tablet having its radial direction set in the vertical direction (the longitudinal direction) or set inclined.
Specific examples of the filling machine for filling a capsule with flat tablets include a tablet filling apparatus disclosed in JP-A 5-170201 (Patent Document 1). In the tablet filling apparatus, as shown in FIG. 20(A), tablets (t) are supplied from a tablet supply hopper (not shown) into first guide holes (b) in a first tablet guide chute (a) to contain the tablet (t) in a row in each first guide hole (b), and the lowermost one of the tablets (t) thus contained in each first guide hole (b) is contained in each counting hole (d) in a counting plate (c). Next, as shown in FIG. 20(B), the counting plate (c) is slid so that the tablets (t) in the counting holes (d) are fed into tablet holding holes (f) in a tablet holding block (e) which are arranged to be displaced from the first guide holes (b) in the first tablet guide chute (a). This reciprocal sliding motion of the counting plate (c) is repeated a predetermined number of times, whereby the predetermined number of the tablets (t) are contained into and held in each of the tablet holding holes (f). Then, as shown in FIG. 20(C), a shutter plate (g) arranged under the tablet holding block (e) is moved to coincide insertion holes (h) in the shutter plate (g) with the tablet holding holes (f), whereby the lower end surfaces of the tablet holding holes (f) are opened. As a result, the tablets (t) contained in each of the tablet holding holes (f) are passed through each second guide hole (j) in a second tablet guide chute (i), to be fed into each capsule body (m) held in a capsule holding block (k) which is arranged on the lower side of the second guide chute (i). In this manner, each capsule body (m) is filled with the predetermined number of tablets (t).
However, in the case of filling a capsule body with flat tablets by use of this filling machine according to the related art, it is highly possible that the flat tablet fed into the capsule body may come into a standing state, to make it impossible to feed the predetermined number of tablets into the capsule body.
More specifically, the filling machine is so configured that, when the flat tablets (t) are dropped from each tablet holding hole (f) in the tablet holding block (e) into each capsule body (m) held in the capsule holding block (k), the shutter plate (g) is slid so as to open the lower end surface of each tablet holding hole (f). Therefore, the lower end surface of the tablet holding hole (f) is gradually opened from one lateral side. Accordingly, the flat tablet contained in a lowermost part of the tablet holding hole (f) under a flat state may fall in the manner of rolling down while becoming inclined from one lateral side, resulting in that the flat tablet (t) drops into the capsule body (m) under a standing state, i.e., with its radial direction set vertical (longitudinal) or inclined. Thus, the flat tablet (t) under a standing state may be generated in the capsule body (m). Besides, the friction at the time of sliding of the shutter plate (g) may also cause the tablet in the lowermost part of the tablet holding hole (f) to come into a standing state.
Furthermore, when the tablet (t) drops from the tablet holding hole (f) into the capsule body (m) held in the capsule holding block (k), a part of the tablet (t) may make contact with the inner circumferential surface of the hole or with an opening edge of the capsule body (m) which is stepped in relation to the inner circumferential surface, resulting in that the tablet (t) is rotated into a standing state.
If a tablet under a standing state is thus generated in the capsule body (m), the tablet in the standing state would occupy a large space in the vertical (longitudinal) direction in the capsule body (m), making it impossible to contain a predetermined number of tablets (t) into the capsule body (m). In addition, the tablet having failed to be contained into the capsule body (m) and protruding from the capsule holding block (k) may plug up the passage for the tablets, causing the succeeding flat tablets to be blocked in series. In such a situation, the tablets may be broken by the motion of the shutter plate (g), possibly leading to a serious trouble in which the fine chips generated upon the breakage clog up various parts of the system.
Patent Document 1: JP-A 5-170201